Ever since I was a teenager in the renewed Cold War of the 1980s, I have feared losing not only my life, but the lives of everyone, absolutely everyone, in a nuclear conflagration. It is easy to forget that this gravest of all threats to the survival of our planet is still very much with us, every day, as we tweet and cappuccino our way through the first part of the 21st century.

Three years ago, BASIC (British American Security Information Council), which I chair, brought together several members of the UK foreign policy and defence establishment of different political persuasions to investigate the arguments for and against Britain’s retention of a nuclear deterrence and the renewal of the Trident nuclear weapons system.

Perhaps not surprisingly, given its members’ backgrounds, the commission – composed of a former Conservative foreign minister, a former Labour defence secretary, a former leader of the Liberal Democrats, two former diplomats, a scientist, a general, and an academic – concluded that Britain must retain its nuclear weapons to deter what they perceive as tangible threats to national security.

Britain won’t go it alone

The commissioners’ argument was based on only three possible scenarios under which an independent nuclear deterrence might be decisive. One, that Russia or another significantly armed nuclear state might aggressively threaten Britain. Two, that a smaller existing or emerging nuclear state might gain global reach and threaten the UK. Or three, that some other existential threat from bio-weapons or an as yet undeveloped weapon of mass destruction might be arrayed against the UK.

In all three scenarios, they conclude, Britain’s nuclear weapons could act as an effective deterrent. Crucially, they discounted the Blair government’s argument that Trident presented some sort of vague insurance policy against an uncertain world. They believed this argument was dangerous and irresponsible.

While anti-nuclear campaigners might decry the headline conclusions that the commission favours retaining Britain’s nuclear deterrence, they should actually be encouraged by the soft underbelly of the reasons given . It’s worth noting that the commissioners did not agree over the relative probability of the three scenarios they observed, nor the degree to which having a British nuclear deterrence would prove relevant in their prevention.

The commissioners contend that “we cannot expect the United States to shoulder indefinitely the awesome responsibilities that lie in providing extended nuclear deterrence to Europe”, yet where is the evidence that the US would withdraw its commitments should the UK or any other NATO ally face the sort of threats described above?

Indeed, the commissioners conclude: “The relationship with the United States is critical to the maintenance of our nuclear programme and to the broader credibility of the UK’s security and place in the world.” Essentially then, Britain would not have to face these threats alone, and its nuclear programme would lack credibility if they did have to go solo in this barely imagined future.

The road to disarmament

So the real headlines coming out of the Trident commission should be about the absolute rejection of some of the conventional arguments in favour of Trident renewal. The commissioners dismiss the claim that Britain’s status as a global power is dependent upon retaining its nuclear weapons. They also reject the economic arguments concerning jobs and the potential impact on British industry.

Fundamentally, the commission advocates for Britain to take a leadership role in the journey towards disarmament. It recognises unequivocally that:

A world with fewer nuclear weapons and fewer states that possess them is not only a safer world if achieved in a stable and controlled manner, it would also be a very large gain directly for global security.

Even more strikingly, the commissioners agreed, “a world with no nuclear weapons would be a bigger gain still”.

The Trident Commission then, in passages missed entirely by the extensive press coverage last week, has argued for the British government to consider reductions in warhead numbers and changes to its targeting positions; have a stronger policy that makes clear the UK would not threaten the use of nuclear weapons against non-nuclear states or under threat or attack from chemical or biological weapons; and potentially step away from the belief that at least one of our nuclear armed submarines must be on patrol at all times.

Most significant of all, perhaps, the commissioners believe that the Government should consider a further delay to the final decision to renew Trident that is due in 2016. As they make clear, there could be great advantages from further delay in terms of costs, technological developments, and the diplomatic successes that might be possible to make renewal unnecessary. The commission has effectively thrown open the debate on Trident renewal and raised questions about almost every assumption relating to the conviction that Britain absolutely must retain its nuclear weapons, no matter what, and that the decision for renewal must be made soon.

The threat we can’t ignore

This process over the past three years has taught me without doubt, that if we cannot speak openly and honestly with those with whom we assume we disagree, and challenge each other’s perceptions and prejudices, then we will never overcome the massive obstacles we face in dealing with threats to our security.

Britain’s role can appear small and insignificant. But I believe the Trident commissioners’ ability to confront their own assumptions about our nuclear future, consider alternatives, and challenge the conventional, is something we can all learn from. We may not agree with their conclusions. We may be sad, or disappointed, that they have not gone further in their thinking about how to achieve the multilateral disarmament they espouse, but they have started a dialogue that we cannot afford to let fall silent.

The final decision to renew Trident is just two years away. We must make sure that this report is not the end but the beginning of what could be one of the most important debates this country has ever had.